DESCRIPTION: There is a fundamental gap in knowledge as to what the deficits of current in vitro endothelial cell models of vascular complications are; what the benchmarks for a model system should be; and what conditions are necessary to match such a system to human primary vascular tissue. Answering these questions is essential to understanding the biochemistry and improving the success rates of therapeutics for metabolism based vascular diseases. The objective of this proposal is to develop a microfluidic based endothelial cell long term culture system which can both mimic the human vasculature and perform sample preparation for metabolomic analyses. This device will integrate a novel, rapid cell lysing system, in-line extraction of interferents and a metabolite pre-concentration system which is amenable to capillary liquid chromatography-mass spectrometric analysis. The central hypothesis is that metabolite levels from endothelial cells cultured in a human serum- based flow system are equivalent to concentrations of metabolites in human cardiac tissue, but different from the current stagnant endothelial cell culture model. This research is innovative because it integrates critical and novel sample preparation techniques to a flow based biomimetic system for sensitive metabolomic analysis. This proposal is significant because it will allow for evaluation of current endothelial cell models and establish a superior model of vascular disease.